Studies on the Antioxidant/Genoprotective Activity of Extracts of Koelreuteria paniculata Laxm

Oxidative injury arising from reactive oxygen species (ROS) appears as the primary mechanism underlying many of human diseases such as cancer, neurodegenerative disorders, diabetes, inflammation, viral infections, autoimmune pathologies and digestive system disorders. Plant extracts or secondary metabolites have served as antioxidants in phytotherapeutics medicines to protect against various diseases for centuries. Koelreuteria paniculata Laxm. is Chinese traditional medicinal plant used in eye related diseases. The 80% methanol mother extract (KPE) along with its hexane fraction (KPF) from the leaves of Koelreuteria paniculata Laxm. were tested for antioxidant and genoprotective potential. The antioxidant potential was checked using ABTS, DPPH (2,2-diphenyl-2-picryl-hydrazyl), Reducing power and Superoxide anion radical scavenging assay and genoprotective activity against the DNA damage induced by Fenton’s reagent using DNA protection studies. The analysis of free radical scavenging activities of the KPE and KPF revealed a concentration-dependent antiradical activity in all the assays. The KPE exhibited IC50 of 54.54 µg/ml in ABTS, 115 µg/ml in DPPH, 110 µg/ml in reducing power and 135 µg/ml in superoxide anion radical scavenging assay while that KPF was found to be very poor in radical scavenging in all the above assays. The phytochemical analysis showed good amount of phenolic and flavonoid compounds in KPE while the KPF fraction lacks phenolic compounds. The KPE extract and KPF fraction both showed DNA protective effect in Calf thymus/pUC18 DNA protection studies. The activity of KPE may be attributed to its polyphenolic constituents which needs further investigation.